This, along with query sharding, enables the creation of a Beam Source

* internal: improve pubsub javadoc

Specifically show creation of executor, rather than
leaving it up to the reader to figure out how to create
an executor.

1) Fix googleapis#3084. Now `create_site.sh` takes `2 min 50 sec` on my workstation (compared to around `1 hr 30 min` before). Done mostly by disabling unused/incorrect reports generation.
2) Remove unused/incorrect reports (reduces size of generated site by factor of 2). The most time consuming were the cobertura test coverage, code style and dependencies reports:

    2.1) For **cobertura test coverage**, since we were generating the report with `-DdisableTests` flag, the test coverage was constantly reported as 0 with huge reports full of zeros and "red" untested code: https://googlecloudplatform.github.io/google-cloud-java/0.42.1/cobertura/index.html

    2.2) For **code style**: it was far the most time consuming report, results of which are huge and which we ignore and they seem have no real value in our workflow (if it did, we should enforce that rules on build and fix them, instead of generating reports):  https://googlecloudplatform.github.io/google-cloud-java/0.42.1/checkstyle-aggregate.html

    2.3) **Dependencies** report has marginal use, and is the only one I removed not because it was wrong, but was almos useless, but was the second most time consuming report among all (after the code style).

3) Fix `google-cloud-bom` documentation discrepancies (looked completely differently, needed extra configuration, since it is not a child of the main pom)
4) Fix site multimodule cross links (currently https://googlecloudplatform.github.io/google-cloud-java/0.42.1/modules.html is completely broken, for example try clicking on `Google Cloud Java BOM`, `Google Cloud Dataproc` and `Google Cloud Datastore` - all give different results and only dataproc kind of works).

More changes will be done in the context of moving grpc and proto artifacts under google-cloud-java (our maven plugins **need update** and currently **we use deprecated** (unsupported in newer versions) configuration.

Fixes googleapis#3126.

…action (googleapis#2776)

* More fixes

* Fixed findbugs version

* Add tracing to cloud spanner client

* Fix version of findbugs

* Made changes per code review comments

* Fixed dependencies

* Fixes style issues

* Removed empty spaces

* Fixed NPE

* Handles the case of null SampledSpanStore

* Changed error_prone version to 2.1.2

* Changed opencensus version to 0.9.1

* Reverts the change to eclipse prefs file

* Interface for manual transaction manager

* More updates

* Tests for transaction manager.

* Indentation fix

* Fixes TransactionRunner tests and adds 2 more tests

* Addresses codacy comments

* Added snippets in Javadoc

This method already has a snippet. It was manually changed to put under <code> block instead of @code in googleapis#2208 due to javadoc bug
https://bugs.openjdk.java.net/browse/JDK-8130754

When I reran the add snippets tool to add the snippets for a different method, it did not detect the existing snippet on readWriteTransaction and again added the same snippet under @code block which fails. My change removes the duplicate snippet but next time we add a new spanner snippet, we will again run into this issue. Ideally we should fix the add snippet tool to handle this case.

It is hard to do this completely async, but we can use a background
thread so it doesn't block user code.

Fixes googleapis#3065.
Fixes googleapis#3134.

…#3160)

…eapis#3158)

The two features are requirePartitionFilter & field.
Also this moves to using a builder instead of using more `of` methods since the number of combinations is large.

…#3163)

`getJob` returns `null` when a job wasn't actually created - e.g. when you're running a dry run query

* add javadoc test to circleci

* running javadoc on all branches

* re-order tasks

…ns (googleapis#3173)

* Regenerate java clients, bump proto-/grpc-artifacts dependency versions

* .

Don't second-guess the server.

Fixes googleapis#3178.

…leapis#3176)

Fixes googleapis#3149, since JWT tokens are now cached.

(this is to separate cleanup changes from the actual proto/grpc artifacts push, which is huge)
1) Cleanup `pom.xml`s (remove unused/duplicate, partially wrong configuration)
2) Update `versions.txt` to include `proto/grpc` artifacts version (will be pushed immediately after this change is pushed). Also update `bump_versions.py` and `replace_versions.py` to strip whitespaces and support empty lines.
3) Fix License to pint explicitly to `Apache 2.0` license (instead of Google Software License, which contains apache license in it (did compare the text, it is identical). Otherwise all third-party tools do not recognize the license (including github, looks like).
4) Add Andrea and Hanzhen to developers list.

…quirement (googleapis#3214)

)

…g. (googleapis#3212)

…llbacks the change, as all the new files are excluded from build, the old modified files are rolled back to the original state. (googleapis#3229)